This invention is related to a mobile communication system equipped with a portable telephone usable in both a ground system and a satellite system, and a relaying apparatus of this portable telephone.
Referring now to drawings, a description will be made for a conventional mobile communication system equipped with a portable telephone and a relaying apparatus of this portable telephone. FIG. 6 is a block diagram for schematically showing, for instance, an arrangement of the conventional portable telephone disclosed in Japanese Unexamined Patent Application No. 8-70262.
In FIG. 6, reference numeral 1 shows a ground system antenna/radio frequency unit; reference numeral 2 represents an interface of the ground system antenna/radio frequency unit 1; reference numeral 3 indicates a satellite system antenna/radio frequency unit; reference numeral 4 denotes an interface of the satellite system/radio frequency unit 3; reference numeral 5 is a radio control unit; and reference numeral 6 shows an interface for connecting any one of the ground system antenna/radio frequency unit 1 or the satellite system antenna/radio frequency unit 3 with the radio control unit 5.
FIG. 7 is a block diagram for indicating a detailed arrangement of the ground system antenna/radio frequency unit and of the radio control unit of the conventional portable telephone.
In FIG. 7, reference numeral 7 shows an antenna of a ground system, and reference numeral 8 represents a radio frequency unit. Also, reference numeral 9 indicates a receiving IF circuit; reference numeral 10 is a demodulator for demodulating an output signal of the receiving IF circuit 9; reference numeral 11 shows a baseband processing unit for processing an output signal of the demodulator 10; reference numeral 12 indicates a modulator for modulating a signal derived from the baseband processing unit 11; and reference numeral 13 shows a transmitting IF circuit for converting an output signal of the modulator 12 into a transmitting IF signal. Furthermore, reference numeral 14 shows a keyboard connected to the baseband processing unit 11; reference numeral 15 indicates a display unit for displaying a signal derived from the baseband processing unit 11; and reference numeral 16 denotes a transmitter/receiver connected to the baseband processing unit.
Furthermore, FIG. 8 is a block diagram representing, for example, an arrangement of the relaying apparatus of the conventional portable telephone disclosed in Japanese Unexamined Patent Application No. 8-70262.
In FIG. 8, reference numeral 17 shows a satellite system antenna/radio frequency unit; reference numeral 18 is a satellite system antenna; reference numeral 19 indicates a radio frequency unit; and reference numeral 20 shows an interface. Also, reference numeral 21 denotes a repeater connected to the satellite system antenna/radio frequency unit 17; reference numeral 22 indicates an interface; reference numeral 23 represents a frequency converting unit; and reference numeral 24 denotes an interface. Furthermore, reference numeral 25 shows a ground system antenna/radio frequency unit connected to the repeater 21; reference numeral 26 denotes a ground system antenna; reference numeral 27 represents a radio frequency unit; and reference numeral 28 shows an interface.
Next, a description will now be made of operations of the conventional mobile communication system equipped with the portable telephone and the relaying apparatus thereof. A single portable telephone which may be employed in both a mobile communication system of a ground system and another mobile communication system of a satellite system, namely a so-called xe2x80x9cdual mode portable telephone,xe2x80x9d is required to be operable in the mobile communication systems in both of the ground system and the satellite system.
Generally specking, in a ground communication system and a satellite communication system, radio interfaces, for instance, transmission/reception frequencies, modulating/demodulating methods, information transfer speeds and the like are different from each other.
As a result, in a dual mode portable telephone, two sets of antennas and radio frequency units are provided which are operable with respect to the ground communication system and the satellite communication system. Also, as indicated in FIG. 6, the ground system antenna/radio frequency unit 1 and the satellite system antenna/radio go frequency unit 3 are used in the replacement manner.
In the conventional apparatus of FIG. 6, when the portable telephone is used in the ground communication system, the ground system antenna/radio frequency unit 1 is connected to the radio control unit 5 so as to use this portable telephone. When the portable telephone is used in the satellite communication system, the satellite system antenna/radio frequency unit 3 is connected to the radio control unit 5 so as to use this portable telephone.
FIG. 7 is a block diagram for showing a detailed arrangement in the case that the ground system antenna/radio frequency unit 1 is connected to the radio control unit 5. A reception electromagnetic wave from the ground communication system is received by the antenna 7, and then is converted into an IF signal by the radio frequency unit 8.
This IF signal is supplied via the interfaces 2 and 6 and the receiving IF circuit 9 to the demodulator 10 so as to be demodulated. This demodulation signal is converted into a speech signal by the baseband processing unit 11, and then the speech signal is supplied to the transmitter/receiver 16.
Conversely, another speech signal entered from the transmitter/receiver 16 is processed by the baseband processing unit 11, and thereafter the processed speech signal is modulated by the modulator 12. This modulation signal is converted into a transmitting IF signal by the transmitting IF circuit 13, and then this transmitting IF signal is supplied via the interfaces 6 and 2 to the radio frequency unit 8.
In the radio frequency unit 8, the transmitting IF signal is converted into a transmit signal having a frequency fitted to the radio interface of the ground communication system. Then, this transmit signal is transmitted from the antenna 7.
In the ground communication system, as the radio frequency, for example, frequencies in a 900 MHz band are employed. The radio frequency unit 8 has a function to convert the frequencies in the 900 MHz band into IF frequencies.
On the other hand, in the case that the portable telephone is used in the satellite communication system, the satellite system antenna/radio frequency unit 3 is connected to the interface 6 of the radio control unit 5 instead of the ground system antenna/radio frequency unit 1.
Also, an internal arrangement of the satellite system antenna/radio frequency unit is similar to that of the ground system antenna/radio frequency unit 1. In this case, the radio frequency unit 3 owns such a function to convert frequencies used in the satellite communication system, for instance, frequencies in 1.6 GHz and 2 GHz bands into IF frequencies.
Generally speaking, since the modulating systems, the information transfer speeds, and the protocol are different from each other in the ground communication system and the satellite communication system, these items should be switched. As a consequence, a demodulation control signal xe2x80x9caxe2x80x9d and a modulation control signal xe2x80x9cbxe2x80x9d are sent from any one of the ground system antenna/radio frequency unit 1 or the satellite system antenna/radio frequency unit 3 to the demodulator 10, the modulator 12, and the baseband processing unit 11 employed in the radio control unit 5, and thus these items are properly switched.
A demodulation control signal xe2x80x9caxe2x80x9d and a modulation control signal xe2x80x9cbxe2x80x9d are outputted from any one of a ground system or a satellite system antenna/radio frequency unit. That is, the demodulation control signal xe2x80x9caxe2x80x9d and the modulation control signal xe2x80x9cbxe2x80x9d, which correspond to the ground communication system, are outputted from the ground system antenna/radio frequency unit 1, whereas the demodulation control signal xe2x80x9caxe2x80x9d and the modulation control signal xe2x80x9cbxe2x80x9d, which correspond to the satellite communication system, are outputted from the satellite system antenna/radio frequency unit 3.
In a dual mode portable telephone, there are many possibilities that a ground communication system is used in a place where this ground communication system is available, whereas a satellite communication system is used in a place where the ground communication system is not available. However, as to the satellite system, the portable telephone cannot be independently utilized in a basement and an indoor area, where the satellites cannot be directly observed. Therefore, it is conceivable that the satellite relaying apparatus as shown in FIG. 8 is used.
In such a case that the portable telephone is used in the place where the ground communication system cannot be utilized and furthermore in an indoor area where the satellites cannot be directly observed, this satellite relaying apparatus is installed at a window through which the satellites can observe in order that the satellite communication system can be used in the indoor area.
In this case, as the portable telephone, while the ground system antenna/radio frequency unit 1 is connected to the radio control unit 5, this portable telephone is operated as the ground communication system. On the other hand, a reception signal from the satellite communication system is received by the satellite system antenna 18 of the satellite relaying apparatus to be converted into an IF signal by the radio frequency unit 19.
This IF signal is inputted via the interfaces 20 and 22 into the frequency converting unit 23. After the frequency of this IF signal is converted, the IF signal having the proper frequency is entered via the interfaces 24 and 28 to the ground system antenna/radio frequency unit 25.
In this ground system antenna/radio frequency unit 25, the frequency-converted IF signal is again converted by the radio frequency unit 27 into the radio frequency of the ground communication system, and thereafter this IF signal having the radio frequency of the ground communication system is transmitted from the antenna 26.
The electromagnetic wave of this ground communication system is received by the ground system antenna 7 of the portable telephone, and the reception signal from the satellite is correctly received by the portable telephone. The transmission signal from the portable telephone is penetrated through a signal path opposite to the above-described signal path, so that the correct communication can be carried out between the satellite and the portable telephone.
The above-described mobile communication system owns a problem. That is, in the case that the satellite communication system is utilized in the indoor area by using the relaying apparatus, if the user tries to directly use the satellite communication system, then the user must replace the ground system antenna/radio frequency unit 1 by the satellite system antenna/radio frequency unit 3 in order to use the portable telephone.
Also, the conventional mobile communication system owns another problem, That is, in such a case that the radio interface such as the modulating system of the ground communication system is different from that of the satellite communication system, the relaying apparatus does not merely perform the frequency converting operation, but must convert the modulating systems.
The present invention has been made to solve the above-explained problems, and therefore, has an object to accomplish a mobile communication system equipped with a portable telephone capable of automatically switching a ground communication system and a satellite communication system without replacing antenna/radio frequency units.
Also, the present invention has been made to solve the above-described problems, and therefore, has an object to accomplish a mobile communication system equipped with a relaying apparatus of a portable telephone capable of utilizing a satellite communication system in an indoor area with employment of a simple arrangement.
A mobile communication system, according to the present invention, is comprised of: a portable telephone useable for automatically switching a ground communication system and a satellite communication system, in which in such a case that while the ground satellite system is not available in a place where a satellite of the satellite communication system cannot observe, an radio interface of the ground satellite system is different from a radio interface of the satellite communication system, a signal process operation is switched in such a manner that an RF signal is processed by the ground communication system, and both in IF signal and a baseband signal are processed by the satellite communication system; and a relaying apparatus for performing a converting operation of the RF signal in the satellite communication system and the RF signal in the ground communication system.
Also, in the mobile communication system according to the present invention, the above-described portable telephone is comprised of: a commonly-used antenna for transmitting/receiving the signal of the ground communication system and also the signal of the satellite communication system; a duplexer connected to the commonly-used antenna for duplexing transmission/reception signals; a first switch for switching an output of the commonly-used antenna; a satellite system receiving radio frequency unit connected to the first switch; a ground system receiving radio frequency unit connected to the first switch; a second switch connected to the satellite system receiving radio frequency unit and to the ground system receiving radio frequency unit; a receiving IF circuit connected to the second switch; a demodulator for demodulating an output of the receiving IF circuit; a baseband processing unit into which the demodulation output of the demodulator is entered; a modulator for modulating an output of the baseband processing unit; a transmitting IF circuit connected to the modulator; a synthesizer for supplying a local signal to the receiving IF circuit and the transmitting IF circuit; a third switch connected to the transmitting IF circuit; a satellite system transmitting radio frequency unit connected to the third switch; a ground system transmitting radio frequency unit connected to the third switch; a fourth switch connected to the satellite system transmitting radio frequency unit and the ground system transmitting radio frequency unit, whose output is supplied to the duplexer; and a CPU for controlling the first, second, third, and fourth switches in the case that while the ground satellite system is not available in the place where the satellite of the satellite communication system cannot observe, the radio interface of the ground communication system is different from the radio interface of the satellite communication system, in such a manner that the ground system receiving radio frequency unit is connected to the ground system transmitting radio frequency unit in response to a first control signal; the synthesizer produces a local signal suitably used to convert the ground system RF signal into an IF signal in response to a second control signal; and the demodulator and the modulator are controlled so as to be operable by the modulating/demodulating methods of the satellite communication system in response to a third control signal.
Also, in the mobile communication system according to the present invention, the above-described portable telephone is comprised of: a satellite system antenna for transmitting/receiving a signal of the satellite communication system; a ground system antenna for transmitting/receiving a signal of the ground communication system; a first duplexer connected to the satellite system antenna, for duplexing the transmission/reception signal of the satellite communication system; a second duplexer connected to the ground system antenna, for duplexing the transmission/reception signal of the ground communication system; a satellite system receiving radio frequency unit connected to the first duplexer; a ground system receiving radio frequency unit connected to the second duplexer; a first switch connected to the satellite system receiving radio frequency unit and to the ground system receiving radio frequency unit; a receiving IF circuit connected to the first switch; a demodulator for demodulating an output of the receiving IF circuit; a baseband processing unit into which the demodulation output of the demodulator is entered; a modulator for modulating an output of the baseband processing unit; a transmitting IF circuit connected to the modulator; a synthesizer for supplying a local signal to the receiving IF circuit and the transmitting IF circuit; a second switch connected to the transmitting IF circuit; a satellite system transmitting radio frequency unit connected to the second switch, the output of which is supplied to the first duplexer; a ground system transmitting radio frequency unit connected to the second switch, the output of which is supplied to the second duplexer; and a CPU for controlling the first, second, third, and fourth switches in the case that while the ground satellite system is not available in the place where the satellite of the satellite communication system cannot observe, the radio interface of the ground communication system is different from the radio interface of the satellite communication system, in such a manner that the first and second switches are controlled so as to connect the ground system receiving radio frequency unit and the ground system transmitting radio frequency unit in response to a first control signal; the synthesizer produces a local signal suitably used to convert the ground system RF signal into an IF signal in response to a second control signal; and the demodulator and the modulator are controlled so as to be operable by the modulating/demodulating methods of the satellite communication system in response to a third control signal.
Also, in the mobile communication system according to the present invention, the above-described portable telephone is comprised of: a commonly-used antenna for transmitting/receiving the signal of the ground communication system and also the signal of the satellite communication system; a duplexer connected to the commonly-used antenna for duplexing transmission/reception signals; a receiving radio frequency unit connected to the duplexer, capable of commonly processing a reception signal of the ground communication system and a reception signal of the satellite communication system; a receiving IF circuit-connected to the receiving radio frequency unit; a demodulator for demodulating an output of the receiving IF circuit;a baseband processing unit into which the demodulation output of the demodulator is entered; a modulator for modulating an output of the baseband processing unit; a transmitting IF circuit connected to the modulator; a synthesizer for supplying a local signal to the receiving IF circuit and the transmitting IF circuit; a transmitting radio frequency unit connected to the transmitting IF circuit, capable of commonly processing a transmission signal of the ground communication system and a reception signal of the satellite communication system; and a CPU for controlling the first, second, third, and fourth switches in the case that while the ground satellite system is not available in the place where the satellite of the satellite communication system cannot observe, the radio interface of the ground communication system is different from the radio interface of the satellite communication system, in such a manner that the ground system receiving radio frequency unit is connected to the ground system transmitting radio frequency unit in response to a first control signal; the synthesizer produces a local signal suitably used to convert the ground system RF signal into an IF signal in response to a second control signal; and the demodulator and the modulator are controlled so as to be operable by the modulating/demodulating methods of the satellite communication system in response to a third control signal.
A mobile communication system, according to the present invention, is comprised of a portable telephone including: a commonly-used antenna for transmitting/receiving a signal of a ground communication system and also a signal of a satellite communication system; a duplexer connected to the commonly-used antenna for duplexing transmission/reception signals; a first switch for switching an output of the commonly-used antenna; a satellite system receiving radio frequency unit connected to the first switch; a ground system receiving radio frequency unit connected to the first switch; a second switch connected to the satellite system receiving radio frequency unit and to the ground system receiving radio frequency unit; a receiving IF circuit connected to the second switch; a demodulator for demodulating an output of the receiving IF circuit; a baseband processing unit into which the demodulation output of the demodulator is entered; a modulator for modulating an output of the baseband processing unit; a transmitting IF circuit connected to the modulator; a synthesizer for supplying a local signal to the receiving IF circuit and the transmitting IF circuit; a third switch connected to the transmitting IF circuit; a satellite system transmitting radio frequency unit connected to the third switch; a ground system transmitting radio frequency unit connected to the third switch; a fourth switch connected to the satellite system transmitting radio frequency unit and the ground system transmitting radio frequency unit, whose output is supplied to the duplexer; and a CPU for controlling the first, second, third, and fourth switches in the case that while the ground satellite system is not available in the place where the satellite of the satellite communication system cannot observe, the radio interface of the ground communication system is different from the radio interface of the satellite communication system, in such a manner that the ground system receiving radio frequency unit is connected to the ground system transmitting radio frequency unit in response to a first control signal; the synthesizer produces a local signal suitably used to convert the ground system RF signal into an IF signal in response to a second control signal; and the demodulator and the modulator are controlled so as to be operable by the modulating/demodulating methods of the satellite communication system in response to a third control signal.
A mobile communication system, according to the present invention, is comprised of a relaying apparatus including: a satellite system antenna installed in a place where while a ground communication system is not available, a satellite of a satellite communication system cannot observe, for transmitting/receiving a signal of the satellite communication system; a first duplexer connected to the satellite system antenna for duplexing transmission/reception signals; a low-noise amplifier for the satellite communication system, connected to the first duplexer for amplifying a reception signal; a down converter connected to the low-noise amplifier for the satellite communication system for converting a frequency of a reception signal; a high power amplifier for the ground communication system, connected to the down converter for amplifying the frequency-converted reception signal; a second duplexer connected to the high power amplifier for the ground communication system for duplexing the transmission/reception signals; a ground system antenna connected to the second duplexer, for transmitting/receiving the signal of the ground communication system; a low-noise amplifier for the ground communication system, connected to the second duplexer for amplifying the transmission signal; an up converter connected to the low-noise amplifier for the ground communication system for converting a frequency of the transmission signal; and a high power amplifier for the satellite communication system, connected to the up converter for amplifying the frequency-converted transmission signal.